Hydrophilic iol packaging system

ABSTRACT

A method of maintaining a hydrophilic intraocular lens in a foldable state without immersing the intraocular lens in liquid water includes the step of storing the foldable intraocular lens within a substantially air tight package containing a water reservoir not in direct contact with the lens.

RELATED APPLICATION

This application claims priority from U.S. Patent Application Ser. No.61/895,184, entitled “Hydrophilic IOL Packaging System,” filed Oct. 24,2013, the entirety of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to packaging methods and systems, andmore specifically to packaging methods and systems for foldableintraocular lenses.

BACKGROUND OF THE INVENTION

IOL polymers can be broadly categorized into two groups: (1) materialsthat absorb less than 1 percent water and (2) materials that absorb morethan 1 percent water. Materials that absorb less than one percent waterare typically referred as hydrophobic polymers. Hydrophobic polymers maybe foldable at room temperature. Their “foldability” results from theircomposition rather than from water acting as a plasticizer. Waterabsorbing polymers are typically referred to as hydrophilic polymers orhydrogels. The most common materials in this group have approximately 25percent water by weight. Hydrophilic polymers are usually foldable atroom temperature by virtue of absorbed water acting as a plasticizer.

The conventional thinking in the intraocular lens (IOL) industry is thathydrophilic IOLs must be immersed in water or saline during storage tomaintain a level of hydration needed for foldability at roomtemperature. Accordingly, lenses composed of these materials are almostalways packaged in normal saline (0.9 percent sodium chloride). Suchlenses may reside in saline for up to five years prior to implantation.The normal saline, in which these lenses are packaged, is generallydesigned to mimic the conditions of the anterior segment of the eyewhere the lens will reside following implantation. This means thatlenses will have similar dimension and mechanical characteristics in theeye as they have in the package where they reside prior to implantation.

Immersion in water or saline in the presence of other plastics neededfor retention or insertion of the IOL, however, can result incontamination of the IOL by chemical entities contained in or producedby other plastic components in the packaging system. Being immersed inwater or saline, the IOL can “communicate” with plastic components viathe liquid phase. Also, when an insertion instrument is removed from thepackage for use, water can flow from where the instrument was storedwithin the package to the IOL.

The packaging of IOL' s in water or saline has the additionaldisadvantage, especially when the IOL is packaged with an insertioninstrument, of increasing the weight of the package, thereby increasingshipping costs.

SUMMARY OF THE INVENTION

The invention avoids the aforementioned problems in the prior art. Inone aspect of the invention, the invention is a method of maintaining ahydrophilic intraocular lens in a foldable state without immersing theintraocular lens in liquid water. The method comprises the step ofstoring the foldable intraocular lens within a substantially air tightpackage containing a water reservoir not in direct contact with thelens.

In another aspect of the invention, the invention is a combinationcomprising: (a) a substantially air tight container having a waterreservoir; and (b) a foldable hydrophilic intraocular lens disposedwithin the container so as not to be in direct contact with the waterreservoir.

DRAWINGS

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription, appended claims, and accompanying drawings where:

FIG. 1 is an upper side perspective view of a container usable in theinvention;

FIG. 2 is a lower side perspective view of the container illustrated inFIG. 1;

FIG. 3 is a bottom view of the container illustrated in FIG. 1;

FIG. 4 is a side view of the container illustrated in FIG. 1;

FIG. 5 is an end view of the container illustrated in FIG. 1;

FIG. 6 is a top view of the container illustrated in FIG. 1, showingretention of an IOL and an IOL injector;

FIG. 7 is an exploded perspective view of a combination having featuresof the invention;

FIG. 8 is a cross-sectional detail view of a first distribution enhancerusable in the embodiment illustrated in FIG. 7;

FIG. 9 is a cross-sectional detail view of a second distributionenhancer usable in the embodiment illustrated in FIG. 7;

FIG. 10 is a cross-sectional detail view of a third distributionenhancer usable in the embodiment illustrated in FIG. 7;

FIG. 11 is a cross-sectional detail view of a fourth distributionenhancer usable in the embodiment illustrated in FIG. 7; and

FIG. 12 is a perspective view of the embodiment illustrated in FIG. 7disposed within a foil pouch.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion describes in detail one embodiment of theinvention and several variations of that embodiment. This discussionshould not be construed, however, as limiting the invention to thoseparticular embodiments. Practitioners skilled in the art will recognizenumerous other embodiments as well.

Definitions

As used herein, the following terms and variations thereof have themeanings given below, unless a different meaning is clearly intended bythe context in which such term is used.

The terms “a,” “an,” and “the” and similar referents used herein are tobe construed to cover both the singular and the plural unless theirusage in context indicates otherwise.

As used in this disclosure, the term “comprise” and variations of theterm, such as “comprising” and “comprises,” are not intended to excludeother additives, components, integers, ingredients or steps.

The Invention

In one aspect of the invention, the invention is a method of maintaininga hydrophilic intraocular lens in a foldable state without immersing theintraocular lens in liquid water. The method comprises the step ofstoring the foldable intraocular lens within a substantially air tightpackage containing a water reservoir not in direct contact with thelens.

As used within this application, the word “foldable” means sufficientlypliable to allow the lens to be rolled into a cylinder with an externaldiameter sufficiently small to permit the lens to be injected into theeye of a patient through an injection tube having a diameter of 2 mm orless. As used herein, the phrase “not to be in direct contact with thelens” means that the water reservoir does not immerse more than theouter edges of the intraocular lens.

The inventors have discovered the surprising fact that sufficienthydration of a hydrophilic lens can be maintained to the extent neededfor folding and insertion into an eye without immersion of the lens in aliquid. In the invention, this is accomplished by packaging the IOL withwater saturated air, or nearly saturated air. By “nearly saturated” itis meant a humidity level of at least about 90%, preferably at least95%. When saturated, such air cannot accept water from a hydrophilicIOL, and when nearly saturated, such air can only accept a minimalamount of water from a hydrophilic IOL. When the air within thecontainer is nearly saturated and the volume of such air within thecontainer is minimal (e.g. less than 100 cubic centimeters), the loss ofwater from the IOL is unimportantly small.

Moreover, virtually any cycling of temperature within the sealed IOLpackage during storage results in temperatures which fall below thepackage interior's dew point and which causes condensation upon the IOL.Even small decreases in the package temperature may cause the air withinthe package to reach its dew point—thus resulting in condensation on allsurfaces with the package, including on those of the IOL. The presenceof water droplets on the IOL's surfaces assures a level of hydrationadequate for foldability and delivery through a small diameter tube.

In a second aspect of the invention, the invention is a combination 10comprising: (a) a substantially air tight container 12 having a waterreservoir 14; and (b) a foldable hydrophilic intraocular lens 16disposed within the container 12 so as not to be in direct contact withthe water reservoir 14. One embodiment of the combination 10 isillustrated in the drawings.

FIGS. 1-5 illustrate a substantially air tight container 12 useable inthe invention. By “substantially air tight, it is meant that thecontainer 12 is fully enclosed, but very small amounts of air maydiffuse through the container walls.

In the embodiment illustrated in FIGS. 1-5, the container 12 comprises atray 18 having an elongate compartment 20 bounded by a bottom wall 22,side walls 26 and an elongate top opening 28. In a typical embodiment,the tray 18 can has a length of about 7.8 inches, a width of about 2.75inches and a maximum depth of about 1.0 inches.

The tray 18 can be made from a thermoplastic, such as polypropylene. Inthe embodiment illustrated in FIGS. 1-5, the tray 18 can be made from0.040″ polypropylene.

In the embodiment illustrated in FIGS. 1-5, the tray 18 has acircumferential rim 30 with a raised outer lip 32 surrounding a recessedinner band 34.

The elongate top opening 28 is sealed by a cover 36. The cover 36 of thecontainer 12 is typically provided by a foil lid 38, preferably by amultilayered foil lid 38, to minimize the amount of water lost todiffusion.

The water reservoir 14 provides an amount of water which barely exceedsthat needed to moisture saturate the interior volume of the container 12at temperatures up to those needed for steam sterilization, as well asto form small water droplets throughout the container 12. This amount ofwater should include that which would be lost over the storage durationdue to diffusion through the walls of the container 12.

Typically the amount of free water within the container will range from0.5 to 3 milliliters of water, such as, for example, about 1 milliliter.

The water reservoir 14 can be provided by a variety of one or moredevices. In the embodiment illustrated in FIG. 7, the water reservoir 14comprises water retained within a water permeable pouch 40 disposedbelow the cover 36. The pouch 40 is designed to capture and retain waterwhich is only released as “free” water when atmospheric and other freewater within the container 12 is depleted over time by diffusion throughthe container walls 22 and 24. Typically, the amount of water capturedand retained within the pouch 40 when the container 12 is initiallysealed is between about 5 milliliters and about 20 milliliters. Thepouch 40 can be made, for example, from a Tyvek, a material sold by E.I. du Pont de Nemours and Company of Wilmington, Del.

The pouch 40 effectively minimizes humidity variations throughout thecontainer 12. The pouch 40 may contain distribution enhancers thatfacilitate distribution of water over the length and width of the pouch40 regardless of the container's orientation. In one embodiment, thedistribution enhancers can be provided by a towel 42 with wicking orsponge like properties, such as illustrated in FIG. 9.

As illustrated in FIG. 10, the distribution enhancers can also beprovided by a piece of plastic 44 that has openings 46 in the form ofblind holes (holes defined in one side of the material which do notextend through the material and out the opposite side) that span thesurfaces of the tray 18. The blind holes are capable of retaining freewater to saturate the vapor phase within the container 12.

As illustrated in FIG. 8, the distribution enhancers can also beprovided by a water absorbing polymer 48, such as polyvinyl pyrollidoneor polymethacrylic acid, having a high water content that can bereleased to the atmosphere of the container 12. Preferably, the waterabsorbing polymer 48 defines holes 50, such as blind holes or throughholes in which free water can reside.

As illustrated in FIG. 1, the water reservoir 14 can also be provided byvoid volumes 52 within the container 12. The void volumes 52 are definedseparate from the location within the container 12 of the intraocularlens 16. Preferably, the void volumes 52 are maximized within thecontainer 12 to minimize the potential for humidity gradients within thecontainer 12.

As illustrated in FIG. 11, the water reservoir 14 can also be providedby blind holes 54 in interior surfaces of the tray walls 22 and/or 26where small quantities of free water can reside. Preferably, the blindholes 54 span a majority of the length and width of the tray.

Also as illustrated in FIG. 11, the water reservoir can also be providedby a non-smooth texture 56 on the interior of surfaces of the tray walls22 and/or 26 capable of retaining small amounts of free water.

In all cases, the combination 10 is preferably autoclavable—able towithstand being heated to 121 degrees C. or more for period of a halfhour or more.

As illustrated in FIG. 12, the combination 10 can be further sealedwithin an autoclavable foil pouch 58. Such autoclavable foil pouch 58minimizes the amount of water lost to diffusion, provides a secondsterile barrier and allows the container 12 to be introduced into asterile field.

As illustrated in FIGS. 6 and 7, the intraocular lens 16 can be disposedunfolded within an injector 60, wherein the injector 60 is adapted tofold and inject the intraocular lens 16 into the eye of a patientthrough a cylindrical injection tube 62 having an inside diametersufficiently small to allow for surgical implanting of the lens withminimum trauma to the eye. In a typical embodiment the cylindricalinjection tube 62 has a diameter of 2 millimeters or less.

Having thus described the invention, it should be apparent that numerousstructural modifications and adaptations may be resorted to withoutdeparting from the scope and fair meaning of the instant invention asset forth herein above and described herein below by the claims.

What is claimed is:
 1. A method of maintaining a hydrophilic intraocularlens in a foldable state without immersing the intraocular lens inliquid water, the method comprising the step of storing the foldableintraocular lens within a substantially air tight package containing awater reservoir not in direct contact with the lens.
 2. A combinationcomprising: a) a substantially air tight container having a waterreservoir; and b) a foldable hydrophilic intraocular lens disposedwithin the container so as not to be in direct contact with the waterreservoir.
 3. The combination of claim 2 wherein the container hasinterior surfaces comprising blind holes and wherein the water reservoircomprises water retained within the blind holes.
 4. The combination ofclaim 2 wherein the container has interior surfaces with non-smoothtextures and wherein the water reservoir comprises water retained withinthe surfaces with non-smooth textures.
 5. The combination of claim 2wherein the container comprises void volumes and wherein the waterreservoir comprises water retained within the void volumes.
 6. Thecombination of claim 2 wherein the container contains a water permeablepouch and wherein the water reservoir comprises water retained withinthe water permeable pouch.
 7. The combination of claim 6 wherein thepouch contains an absorbent towel and wherein the water reservoircomprises water retained within the towel.
 8. The combination of claim 6wherein the pouch contains a sheet having blind holes and wherein thewater reservoir comprises water retained within the blind holes.
 9. Thecombination of claim 6 wherein the pouch contains a water absorbingpolymer and wherein the water reservoir comprises water retained withinthe water absorbing polymer.
 10. The combination of claim 2 wherein thecontainer comprises a tray having an elongate compartment bounded by abottom wall, side walls and an elongate top opening, the top openingbeing sealed by a cover, and wherein the water reservoir comprises waterretained within a water permeable pouch disposed below the cover andspanning substantially the entirety of the top opening.
 11. Thecombination of claim 10 wherein the container has a non-permeable foillid.
 12. The combination of claim 2 wherein the container the waterreservoir retains between about 0.5 and 3 ml of water.
 13. Thecombination of claim 2 wherein the combination is disposed within anautoclavable foil pouch.
 14. A combination comprising: a) asubstantially air tight container comprises a tray having an elongatecompartment bounded by a bottom wall, side walls and an elongate topopening, the top opening being sealed by a cover; comprises waterretained within a water permeable pouch disposed below the cover andspanning substantially the entirety of the top opening; b) a waterreservoir comprising between about 0.5 and 3 ml of water retained withina water permeable pouch disposed below the cover and spanningsubstantially the entirety of the top opening; and c) a foldablehydrophilic intraocular lens disposed unfolded within an injector, theinjector being adapted to fold and inject the intraocular lens into theeye of a patient through a cylindrical injection tube having an insidediameter of 2 mm or less; wherein, the hydrophilic intraocular lens isdisposed within the container so as not to be in direct contact with thewater reservoir.
 15. The combination of claim 14 wherein the pouchcontains an absorbent towel and wherein the water reservoir compriseswater retained within the towel.
 16. The combination of claim 14 whereinthe pouch contains a sheet having blind holes and wherein the waterreservoir comprises water retained within the blind holes.
 17. Thecombination of claim 14 wherein the pouch contains a water absorbingpolymer and wherein the water reservoir comprises water retained withinthe water absorbing polymer.
 18. The combination of claim 14 wherein thecombination is disposed within an autoclavable foil pouch.